Overall I still gives 2 thumbs up for the Arduino team. Though I had a less than perfect product delivered, I consider it a temporary problem and I am sure things will be fixed in the supply channel fairly quickly.

I am simply stating that they have occurred to add creditability to the original poster (not an isolated incident). I am sure most of us have the required skills to fix the anomalies. In my case, I was able to apply some heat and give things a yank in the right direction.

I see 150 mils (0.15 inch) spacing between the headers in question on the Eagle .brd file for the Mega2560 (same as the .brd file for the Mega1280).

My Observation And Opinion On Whether It Makes A Difference:

I have Mega1280 and a Mega protoshield and a number of "regular" Arduino shields. The springy nature of the pins makes the difference (0.010 inches) utterly irrelevant when plugging the boards together. Really.

I mean, I had no idea that there was this Monstrous Discrepancy until I read about it here and decided to check it out on the drawing.

Just my two cents worth. (See Footnote.)

Regards,

Dave

Footnote:I know that Engineers want things to be absolutely perfect, but even though I just this morning read that the brand new Hoover Dam Bypass Bridge was off by almost 3/8 of an inch when the two halves met, I'll still drive over it the first chance I get.

Not trying to make 0.01" seem significant. It's 1/3 the size of the pins by the way. If you solder your own shield, no big deal. The holes provide enough wiggle room. If you buy a pre-soldered shield, the odds may play against you a little bit, but you may just force it. I was just trying to see if the Arduino people have changed anything and the answer is no (almost not).

I don't know how you did it but my downloaded board is showing 0.16". You need to hold down the ALT when measuring. Showing the grid will make this very clear. The middle header is on the 0.05" grids and the left header is not, a bit to the left.

Zoom the drawing until the pads marked "7" and "8" on the PWM row of headers are really big on the screen.

Click the "Mark" icon on the left tool bar (Second down on the right-hand column)

Place the cursor at the exact center of the hole in the pad marked "8" on the PWM header. There is a big + that shows the center.

Left-click the mouse. In the measurement window I read (R 0 0) (P 0 0). These are rectangular and polar coordinates, respectively, of the reference point. (Actually there is a "degree" symbol on the second P coordinate, but I won't try to reproduce it here.)

Anyhow...

You can see those coordinate numbers change as you move the mouse (don't click it again; just move it around.)

So...

Move the cursor to the exact center of the hole in the pad marked "7" on the PWM header.

I see 150 mils (0.15 inch) spacing between the headers in question on the Eagle .brd file for the Mega2560

the .BRD file currently downloadable from arduino.cc has apparently been fixed, and has the 160 mill separation. The .brd file for the 2560 that was initially published had a 150mil separation like the old MEGA.

All I have here is a low-res web cam (will give it a try on something more hi-rez).

BTW, There are two "serial numbers" on the package.One on the side with a bar-code and one on the top next to the quality seal stating the reseller web site URL and a different number under it.

I ordered it from a reseller in Italy 11 days ago.

You could never guess the size of the thing unless you hold it in your hand.

My first reaction was: "this envelope is empty". After that I tried to cut my finger off - no luck.

There was something that reminded me of "solder evaporation residue" barely noticeable close to the RESET-EN. After touching it - it was like some thin layer of paste that could be smudged away easily. No smell or taste. pH neutral and obviously not poisonous (so far).

The silkscreen showing 5V next to the header is missing the bottom half of the number 5 -- (Will this work with 0021?!?!)

All through hole components are close to the board, under a 90 degree angle.

The bottom side of the board is clean, all solder points OK, no flaws in the silk screen.

I guess it's time to plug it in. (if I see any Morse Code will let you know).

the .BRD file currently downloadable from arduino.cc has apparently been fixed, and has the 160 mill separation

OK, I get it.

And now, for my last words on this thread (I promise):

I have already indicated that the 150 mil separation on the original Mega board (the 1280) presents no problem for me. If other people say it's a problem for them, I won't argue.

A problem that I do have is with documentation. The downloadable design file for the Mega2560 has the same name as the file that I downloaded on October 1 (when the world was young and I was still an Arduino Idealist). When I unzip the current download file, the .brd and .sch files have the same names as the older one, but the current .brd file has a date of October 10, whereas the original one had a date of September 26. (The .sch files have the same date, September 26, but the times are slightly different.)

I see no difference between the two schematic files (but I didn't look very hard).

The only difference that I observe between the two board files is that the "PWMH" header was nudged to the left 0.010 inches (10 mils) so that the separation is, indeed, 0.16 inches (160 mils). I am quite sure that I wouldn't have noticed that if I hadn't been looking for the specific coordinates.

More important (to me, at least) is the following:

I see no indication of revision number on the schematics or the boards themselves. So here are a few questions that I have. (Since I won't be replying, you can consider them rhetorical, although I wouldn't mind seeing opinions of anyone who chooses to express them.)

Shouldn't there be something on the silkscreen (or copper) on the board to indicate which revision people are actually holding in their hot little hands?

Shouldn't these revisions be documented somewhere?

Shouldn't download file names be changed when the contents change?

Of course, I may be missing something. It wouldn't be the first time (not even the first time today).

It is just the blink duration, it is not going to say Morse Code or anythingYou will see that the number one is one dot (short flash) followed by four dashes (or long flash).The ratio between a dot and a dash is 3 to 1 but the absolute time of a dot is not defined.

Note depending on where you start it could be saying 9 but one for UNO is much more likely.